Design for touch and small screens
For a technical producer, this purchase confirmation prototype should make every player action and player-visible outcome easy to evaluate. Write how to show the exact item, Koin amount, balance impact, and explicit confirm/cancel actions. Map preview, confirmation, cancelling the action, an insufficient balance, pending, success, delivery, owned, and reload. Give every failure a safe next action. Use comfortably separated confirm and cancel controls, readable Koin amounts, and a layout that survives portrait, landscape, browser chrome, and an on-screen keyboard without hiding the item.
Expect interruption
Simulate locking the phone, changing tabs, receiving a call, and returning with a slow connection. The player should see one understandable result and retain a safe route back to play.
State the platform limit
A mobile browser prototype is not an App Store or Google Play binary. Native billing APIs, device identity, refunds, entitlements, and submission need separate implementation and review.
Name every state and owner
Separate preview, confirmation, pending, success, delivery, owned, insufficient Koin, cancel, interrupted, and reopened states. Assign later production work for identity, persistence, native billing, security, refunds, policy, and monitoring.
Define idempotent recovery
Repeated confirmation, a slow response, navigation during delivery, and reopening must resolve to one result. Record which state is authoritative and how the player can safely retry without another grant or Koin deduction.
Turn the prototype into tickets
Capture the visible behavior first, then create implementation tasks with expected examples for each transition and platform boundary. Do not translate a working browser interaction into an unsupported claim that backend commerce is complete.
Repeat the complete choice
The confirmation should repeat the selected item, exact Koin amount, visible Koin balance, remaining balance, and ownership rule without introducing a different offer. Test that behavior using mobile web games. Mobile web is not the same as an App Store or Google Play binary.
Separate confirm from cancel
Use distinct actions with clear labels and enough spacing for the target input method. Returning to the game should never spend Koin. Test that behavior using mobile web games. Mobile web is not the same as an App Store or Google Play binary.
Prevent repeated confirmation
After confirmation, show a pending state and disable repeated input until the result is known. A slow response should not create duplicate grants. Test that behavior using mobile web games. Mobile web is not the same as an App Store or Google Play binary.